KR20220038057A - A polyester resin, and a molded article, a stretched film, and a bottle containing the polyester resin - Google Patents

Abstract

A polyester resin comprising a dicarboxylic acid structural unit and a diol structural unit, wherein more than 0 mol% and 20 mol% or less of the diol structural unit is a unit derived from a diol having a cyclic acetal skeleton, the diol structural unit 70 to 98 mol% of the unit is a unit derived from a diol having an alicyclic skeleton, and a unit derived from ethylene glycol is included in the diol structural unit, and 80 mol% or more of the dicarboxylic acid structural unit A polyester resin that is a unit derived from terephthalic acid and has physical properties represented by the following (A). (A) The minimum value of semi-crystallization time based on the depolarization intensity method when melting at 280°C and crystallizing at constant temperature at 150 to 230°C is 600 seconds or less.

Description

A polyester resin, and a molded article, a stretched film, and a bottle containing the polyester resin

The present invention relates to a polyester resin, and a molded article, a stretched film, and a bottle containing the polyester resin.

Aromatic saturated polyester resin, especially polyethylene terephthalate (hereinafter sometimes referred to as "PET"), is a resin with a balance in mechanical performance, solvent resistance, odor retention, weather resistance, recyclability, etc. It is widely used mainly for its purpose. However, PET has improvements in heat resistance. In other words, since the glass transition temperature of PET is about 80 ° C, high heat resistance such as products used in automobiles, packaging materials for import and export, food packaging materials subjected to retort treatment or microwave heating, baby bottles or tableware subjected to heat sterilization treatment, It can be said that it is not suitable for a use requiring transparency.

On the other hand, as PET with improved heat resistance, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (hereinafter, PET obtained by copolymerizing "spiroglycol" or "SPG" in some cases) and 1,4-cyclohexanedimethanol (hereinafter sometimes referred to as "CHDM") is mentioned ( For example, refer to the following Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 2003-183423 Japanese Patent Laid-Open No. 2003-292593

From the viewpoint of forming a stretched molded article that is excellent in heat resistance and transparent (eg, stretched film, etc.), in addition to using a resin having a high Tg, it is also possible to use a polyester resin that is not amorphous but has crystallinity. become a means

For example, in order to increase the degree of crystallinity and to improve the heat resistance of the resin, it is also an effective means to perform stretching orientation crystallization at a temperature higher than Tg.

Here, normal PET has a low Tg, but a high crystallization rate, so that it is possible to perform stretching orientation crystallization at a temperature higher than Tg while maintaining transparency. However, although the glass transition temperature (Tg) of PET which copolymerized SPG and CHDM is higher than normal PET, the crystallization rate is slow. For this reason, stretching orientation crystallization cannot be performed at a temperature higher than Tg, and PET which copolymerized SPG and CHDM is handled as an amorphous resin.

On the other hand, in fields requiring heat resistance, polyester resins such as poly(1,4-cyclohexanedimethylene terephthalate) (hereinafter sometimes referred to as “PCT”) having a high glass transition temperature are used. come. However, although PCT also improves heat resistance, crystallinity is high and transparency is inferior.

For example, although PCT has a higher Tg than PET, conversely, since the crystallization rate is too fast, it is difficult to manufacture an injection molded article or perform extrusion molding while maintaining transparency. For this reason, for example, by modifying PCT with ethylene glycol (hereinafter, may be referred to as "EG") or isophthalic acid (hereinafter referred to as "PIA") or the like, the crystallization rate of PCT is reduced. It can be slowed down to PET level. However, in these modified PCTs, although transparency is improved with respect to PET, Tg also falls to PET level with the fall of a crystallization rate, and heat resistance will be inferior.

As mentioned above, the polyester resin used conventionally still has room for improvement in that it forms the molded object excellent in heat resistance and transparency.

An object of the present invention is to provide a polyester resin capable of forming a molded article having excellent heat resistance and transparency, and a molded article, a stretched film, and a bottle containing the polyester resin in order to solve the above problems.

<1> A polyester resin comprising a dicarboxylic acid structural unit and a diol structural unit, wherein more than 0 mol% and 20 mol% or less of the diol structural unit is a unit derived from a diol having a cyclic acetal skeleton; 70 to 98 mol% of the diol structural unit is a unit derived from a diol having an alicyclic skeleton, and a unit derived from ethylene glycol is included in the diol structural unit, and 80 mol of the dicarboxylic acid structural unit % or more is a unit derived from terephthalic acid, and a polyester resin having physical properties represented by the following (A).

(A) The minimum value of semi-crystallization time based on the depolarization intensity method when melting at 280°C and crystallizing at constant temperature at 150 to 230°C is 600 seconds or less.

<2> The polyester resin according to <1>, wherein the diol having a cyclic acetal skeleton is at least one selected from compounds represented by the following formulas (1) and (2).

[Formula 1]

(In formula (1), R ¹ and R ² each independently represent an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms.)

[Formula 2]

(in formula (2), R< ¹ > is the same as that of formula (1), and R< ³ > represents a C1-C10 aliphatic group, a C3-C10 alicyclic group, or a C6-C10 aromatic group. )

<3> The diol having a cyclic acetal skeleton is 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane Phosphorus, the polyester resin according to <1> or <2>.

<4> The polyester resin according to any one of <1> to <3>, wherein the diol having an alicyclic skeleton is 1,4-cyclohexanedimethanol.

<5> The polyester resin according to any one of <1> to <4>, wherein the content of the unit derived from ethylene glycol among the diol structural units is 0.1 to 10 mol%.

<6> A molded article comprising the polyester resin according to any one of <1> to <5>.

<7> Stretched film comprising the polyester resin according to any one of <1> to <5>.

<8> A bottle containing the polyester resin according to any one of <1> to <5>.

ADVANTAGE OF THE INVENTION According to this invention, the polyester resin which can form the molded object which has outstanding heat resistance and transparency, and the molded object containing this polyester resin, a stretched film, and a bottle can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, the form (Hereinafter, it is simply called "this embodiment") for implementing this invention is demonstrated in detail. However, the following embodiment is an illustration for demonstrating this invention, and is not the meaning which limits this invention to the following content. The present invention can be implemented by appropriately deforming within the scope of the gist.

<< polyester resin >>

The polyester resin of this embodiment is a polyester resin containing a dicarboxylic acid structural unit and a diol structural unit,

More than 0 mol% and 20 mol% or less of the diol structural unit is a unit derived from a diol having a cyclic acetal skeleton,

70 to 98 mol% of the diol structural unit is a unit derived from a diol having an alicyclic skeleton,

A unit derived from ethylene glycol is included in the diol structural unit,

80 mol% or more of the dicarboxylic acid structural unit is a unit derived from terephthalic acid,

It has the physical property shown by following (A).

(A) The minimum value of semi-crystallization time based on the depolarization intensity method (hereinafter, sometimes simply referred to as “crystallization rate”) when melted at 280°C and crystallized at 150-230°C at constant temperature is 600 seconds or less

The polyester resin of the present embodiment contains, in the diol structural unit, a unit derived from a diol having a cyclic acetal skeleton, a unit derived from a diol having an alicyclic skeleton, and a unit derived from ethylene glycol. ; Since content of the unit derived from terephthalic acid in a dicarboxylic acid structural unit exists in a specific range, and since the crystallization rate is 600 second or less, it has crystallinity and Tg is also high. Moreover, the polyester resin of this embodiment can perform extending|stretching orientation crystallization at a temperature higher than Tg as it is maintaining transparency. Thereby, by using the polyester resin of this embodiment, the molded object which has the outstanding heat resistance and transparency can be formed.

<Diol constituent unit>

The polyester resin of this embodiment contains the following units at least as said diol structural unit.

Units derived from diols having a cyclic acetal skeleton: more than 0 mol% and not more than 20 mol%

- Units derived from diols having an alicyclic skeleton: 70 to 98 mol%

Units derived from ethylene glycol

(Unit derived from a diol having a cyclic acetal skeleton)

The polyester resin of the present embodiment has, as a diol structural unit, a unit derived from a diol having a cyclic acetal skeleton.

Although it does not specifically limit as "diol which has a cyclic acetal skeleton" used as the origin of the said unit, For example, At least 1 sort(s) selected from the compound (diol) represented by following formula (1) and Formula (2) desirable. When the compounds represented by the following formulas (1) and (2) are used as the diol having a cyclic acetal skeleton, the transparency and heat resistance of the resulting molded article tend to be more improved.

[Formula 3]

(In formula (1), R ¹ and R ² each independently represent an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms.)

[Formula 4]

(in formula (2), R< ¹ > is the same as that of formula (1), and R< ³ > represents a C1-C10 aliphatic group, a C3-C10 alicyclic group, or a C6-C10 aromatic group. )

In Formulas (1) and (2), R ¹ and R ² are each independently (only R ¹ in Formula (2)), an aliphatic group having 1 to 10 carbon atoms, or an alicyclic group having 3 to 10 carbon atoms. , or an aromatic group having 6 to 10 carbon atoms, preferably a methylene group, an ethylene group, a propylene group, a butylene group, or a structural isomer thereof, for example, an isopropylene group or an isobutylene group.

In formula (2), R ³ is an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, butyl group or structural isomers thereof, for example, isopropyl group and isobutyl group.

Examples of the diol having a cyclic acetal skeleton represented by the formula (1) include 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxa Spiro[5.5]undecane is particularly preferable, and as the diol having a cyclic acetal skeleton represented by formula (2), 5-methylol-5-ethyl-2-(1,1-dimethyl-2-hydro Particular preference is given to oxyethyl)-1,3-dioxane. Among these, as the diol having a cyclic acetal skeleton, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (SPG ) is particularly preferred.

(Unit derived from a diol having an alicyclic skeleton)

The polyester resin of the present embodiment has, as a diol structural unit, a unit derived from a diol having an alicyclic skeleton. The polyester resin of this embodiment can improve heat resistance and crystallinity by including the unit derived from the diol which has an alicyclic skeleton.

Although it does not specifically limit as "diol which has an alicyclic skeleton" used as the origin of the said unit, For example, 1, 3- cyclohexane dimethanol, 1, 4- cyclohexane dimethanol, 1,2 - Decahydronaphthalenedimethanol, 1,3-decahydronaphthalenedimethanol, 1,4-decahydronaphthalenedimethanol, 1,5-decahydronaphthalenedimethanol, 1,6-decahydronaphthalenedimethanol, 2,6 and diols such as decahydronaphthalenedimethanol, 2,7-decahydronaphthalenedimethanol, tetralindimethanol, norbornenedimethanol, tricyclodecanedimethanol, and pentacyclododecanedimethanol, 1, Preference is given to 4-cyclohexanedimethanol, norbornenedimethanol, tricyclodecanedimethanol, 2,6-decahydronaphthalenedimethanol, and 1,4-cyclohexanedimethanol (CHDM) is particularly preferred.

(Ethylene Glycol)

The unit derived from ethylene glycol is contained in the diol structural unit of this embodiment. Since the polyester resin of this embodiment contains the unit derived from ethylene glycol, when synthesize|combining resin, it is easy to couple|bond each monomer, and productive efficiency can be raised.

(Other diol units)

The polyester resin of this embodiment may also contain other diol structural units other than the unit derived from the diol unit which has a cyclic acetal skeleton, the unit derived from the diol which has an alicyclic skeleton, and the unit derived from ethylene glycol. Examples of other diol structural units include trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, propylene glycol , aliphatic diols such as neopentyl glycol; polyether compounds such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; 4,4'-(1-methylethylidene)bisphenol, methylene bisphenol (bisphenol F), 4,4'-cyclohexylidene bisphenol (bisphenol Z), 4,4'-sulfonyl bisphenol (bisphenol S), etc. of bisphenols; alkylene oxide adducts of the bisphenols; aromatic dihydroxy compounds such as hydroquinone, resorcin, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxydiphenyl benzophenone; and units derived from diols such as alkylene oxide adducts of the aromatic dihydroxy compound.

(Content of each structural unit in the diol structural unit)

Content of the unit derived from the diol which has a cyclic acetal skeleton among all the diol structural units is more than 0 mol% and 20 mol% or less. When the content of the unit having a cyclic acetal skeleton is 0 mol%, heat resistance decreases, and when it exceeds 20 mol%, the crystallinity of the polyester resin decreases and heat setting after stretching becomes difficult. From the viewpoint of heat resistance and crystallinity, the content of the unit derived from the diol having a cyclic acetal skeleton is preferably 8 mol% or more and 20 mol% or less, and more preferably 10.1 mol% or more and 20 mol% or less.

Content of the unit derived from the diol which has an alicyclic skeleton among all the diol structural units is 70-98 mol%. If the content of the unit derived from the diol having an alicyclic skeleton is less than 70 mol%, the crystallinity of the polyester resin decreases and heat setting after stretching becomes difficult, and if it exceeds 98 mol%, the crystallization rate of the polyester resin is too fast. Therefore, it becomes difficult to shape|mold as it is maintaining transparency. From the viewpoint of heat resistance and crystallinity, the content of the unit derived from the diol having an alicyclic skeleton is preferably 70 to 95 mol%, more preferably 75 to 90 mol%.

When the content of the unit derived from ethylene glycol among all the diol structural units is 0 mol%, it is difficult to bind the respective monomers when synthesizing the resin, and the production efficiency deteriorates. From the viewpoint of production efficiency and crystallinity, the content of the unit derived from ethylene glycol is preferably 0.1 to 10 mol%, more preferably 0.1 to 8 mol%, and particularly preferably 0.1 to 5 mol%.

<Dicarboxylic acid structural unit>

(unit derived from terephthalic acid)

The polyester resin of this embodiment contains 80 mol% or more of units derived from terephthalic acid at least as a dicarboxylic acid structural unit. If content of the unit derived from terephthalic acid is less than 80 mol% among all the dicarboxylic acid structural units, the crystallinity of a polyester resin will fall and the heat setting after extending|stretching will become difficult. From the viewpoint of crystallinity, the content of the unit derived from terephthalic acid is preferably 80 to 100 mol%, more preferably 90 to 100 mol%, and particularly preferably 95 to 100 mol%.

(Other dicarboxylic acid constituent units)

The dicarboxylic acid structural unit in the polyester resin of this embodiment may contain other dicarboxylic acid units other than the unit derived from terephthalic acid.

Examples of other dicarboxylic acid units include, but are not limited to, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, Cyclohexanedicarboxylic acid, decalindicarboxylic acid, norborneindicarboxylic acid, tricyclodecanedicarboxylic acid, pentacyclododecaindicarboxylic acid, 3,9-bis(1,1-dimethyl-2-carboxyethyl)-2, Aliphatic di such as 4,8,10-tetraoxaspiro[5.5]undecane, 5-carboxy-5-ethyl-2-(1,1-dimethyl-2-carboxyethyl)-1,3-dioxane units derived from carboxylic acids; Isophthalic acid, phthalic acid, 2-methylterephthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetralindi and units derived from aromatic dicarboxylic acids such as carboxylic acids.

<Other units>

In the polyester resin of this embodiment, in the range which does not impair the objective of this embodiment, monoalcohol units, such as butyl alcohol, hexyl alcohol, and octyl alcohol, trimethylol propane, glycerol, 1,3,5-pentane tri Trihydric or higher polyhydric alcohol units such as ol and pentaerythritol, monocarboxylic acid units such as benzoic acid, propionic acid and butyric acid, polyhydric carboxylic acid units such as trimellitic acid and pyromellitic acid, glycolic acid, lactic acid, hydroxybutyric acid, 2 - You may also contain oxy acid units, such as hydroxyisobutyric acid and hydroxybenzoic acid.

When the polyester resin of this embodiment contains other structural units other than a diol structural unit and a dicarboxylic acid structural unit, from a viewpoint of fully exhibiting the effect of this invention, the content rate of the said other structural unit is a polyester resin It is preferable that it is 3.0 mass % or less with respect to the whole, and 1.0 mass % or less is more preferable.

<Polyester resin>

Moreover, the molar ratio [O/C] of the diol structural unit (O) and the dicarboxylic acid structural unit (C) in the polyester resin of this embodiment is 90/100 - 110/100 from a viewpoint of heat resistance and crystallinity. This is preferable, 95/100 to 105/100 are more preferable, and 99/100 to 101/100 are especially preferable.

Although the weight average molecular weight of the polyester resin of this embodiment is not specifically limited, From a viewpoint of heat resistance and impact resistance, 10,000-200,000 are preferable, 20,000-150,000 are more preferable, and 30,000-100,000 are especially preferable. The said weight average molecular weight can be measured by the gel permeation chromatography (GPC) which used monodisperse polystyrene as a standard substance, for example.

The method for manufacturing the polyester resin of this embodiment is not specifically limited, A conventionally well-known method is applicable. For example, a melt polymerization method, such as a transesterification method and a direct esterification method, or a solution polymerization method etc. are mentioned. Various stabilizers, such as a transesterification catalyst, an esterification catalyst, an etherification inhibitor, a heat stabilizer, and an optical stabilizer, a polymerization regulator, etc. conventionally known thing can be used.

The polyester resin of the present embodiment is not particularly limited, but a diol structural unit (a unit derived from spiroglycol (SPG), a unit derived from 4-cyclohexanedimethanol (CHDM), and ethylene glycol) A combination of a lycol (EG)-derived unit) and a dicarboxylic acid structural unit (a terephthalic acid-derived unit) is mentioned.

(Properties)

The polyester resin of this embodiment has the physical property (crystallization rate) shown by following (A).

(A) The minimum value of semi-crystallization time based on the depolarization intensity method when melting at 280°C and crystallizing at constant temperature at 150 to 230°C is 600 seconds or less.

In the polyester resin of this embodiment, if the minimum value of the semi-crystallization time is 600 seconds or less, stretching orientation crystallization can be performed at a temperature higher than the Tg of the resin while maintaining transparency, and sufficient crystallinity can be exhibited.

The semi-crystallization time stipulated in the formula (A) is, specifically, a polyester resin in the form of a sheet, sandwiched between a cover glass, melted at 280° C. for 6 minutes, and then placed in a crystallization bath at a predetermined temperature to obtain a degree of depolarization intensity. The change over time is measured, and the semi-crystallization time at that temperature is determined. The minimum value of the semi-crystallization time is determined by changing the temperature of the crystallization bath from 150 to 230° C. at 10° C. intervals to measure the semi-crystallization time when crystallized at constant temperature, and the minimum value among them is the semi-crystallization time of the resin (seconds) do it with

Although there is no limitation in particular as a crystallization rate of the polyester resin in this embodiment, From a viewpoint of performing manufacture and extrusion molding of an injection-molded article as it maintains the crystallinity of resin, the heat resistance of the molded object obtained, and transparency, 20 to 600 seconds is Preferably, 25 to 500 seconds are more preferable, and 30 to 400 seconds are particularly preferable.

Although there is no limitation in particular as for the glass transition temperature (Tg) of the polyester resin in this embodiment, It is preferable that it is 91 degreeC or more, More preferably, it is 95 degreeC or more, More preferably, it is 100 degreeC or more.

When the glass transition temperature is within the above range, the polyester resin of the present embodiment tends to be more excellent in heat resistance. Accordingly, it can be used in applications requiring high heat resistance, which could not be used in conventional PET or modified PET partially copolymerized with 1,4-cyclohexanedimethanol or isophthalic acid. For example, since it can be used inside a car or in a dock passing through the equator (it is said to reach 70 to 80°C), it is possible to use it in the interior of a car, a container for air freshener used in a car, eye drops, etc., and a blister pack It can be used suitably for packaging materials used for import and export. Moreover, it can use suitably also for the use which performs high temperature processing, such as a food packaging material which performs microwave heating or a retort process, and containers, such as a feeding bottle and tableware, which perform heat sterilization process. The said glass transition temperature can be measured based on the method described in the Example mentioned later. In addition, the said glass transition temperature can be adjusted to the above-mentioned preferable range, for example, by appropriately selecting the dicarboxylic acid structural unit and diol structural unit in the polyester resin of this embodiment based on the above-mentioned preferable aspect. there is.

Moreover, it is preferable that the calorific value of the crystallization peak at the time of temperature fall of the polyester resin of this embodiment is 15 J/g or more, More preferably, it is 20 J/g or more. In addition, the upper limit of the amount of heat of the crystallization peak at the time of temperature drop is not particularly limited, but as a preferable range of the amount of heat of the crystallization peak at the time of temperature fall, 15 to 50 J/g is preferable, and 20 to 50 J/g is more preferable. The calorific value of the crystallization peak at the time of temperature drop is measured using a differential scanning calorimeter, for example, about 10 mg of the sample is placed in an aluminum unsealed container, and the temperature rise rate is 20 ° C./min in a nitrogen gas (30 ml/min) stream. , The exothermic peak that appears when the temperature changed by 1/2 of the difference between the baselines before and after the transition of the DSC curve is set as the glass transition temperature, maintained at 280°C for 1 minute, and then cooled at a temperature decrease rate of 10°C/minute can be measured from the area of

It is preferable that the haze of the 40-micrometer-thick biaxially stretched film obtained by extrusion-molding the polyester resin composition of this embodiment is 1.0 % or less, More preferably, it is 0.5 % or less. When the haze is in the above range, the polyester resin of the present embodiment tends to exhibit higher transparency. A haze can be measured based on the method as described in the Example mentioned later. In addition, the said haze can be adjusted to the preferable range mentioned above, for example by selecting suitably the dicarboxylic acid structural unit and diol structural unit in the polyester resin of this embodiment based on the preferable aspect mentioned above.

[Optional Ingredients]

You may use the polyester resin of this embodiment as a polyester resin composition containing an arbitrary component. Although not limited to the following as an optional component, For example, antioxidant, light stabilizer, ultraviolet absorber, plasticizer, extender, gloss remover, drying regulator, antistatic agent, antisettling agent, surfactant, flow improver, drying oil, waxes, Various additives such as fillers, colorants, reinforcing agents, surface leveling agents, leveling agents and curing reaction accelerators, and molding aids can be added. In addition, as other optional components, polyolefin resin, polyester resin other than the polyester resin of the present embodiment, polyamide resin, polycarbonate resin, acrylonitrile resin, vinyl chloride resin, vinyl acetate resin, polyacrylic acid resin, poly Resins, such as a methacrylic acid resin, polystyrene, ABS resin, polyimide resin, and AS resin, and an oligomer may be included. Although it does not specifically limit as content of an arbitrary component, It is preferable to set it as 2.9 mass % or less with respect to 100 mass % of polyester resin composition from a viewpoint of ensuring good heat resistance and transparency, It is more preferable to set it as 1.0 mass % or less. , 0.5% by mass or less is particularly preferred.

<Use of polyester resin>

The polyester resin of this embodiment and the molded object containing the polyester resin can be used for various uses. For example, the molded object containing a polyester resin can be formed using a polyester resin.

In addition, as described above, since the polyester resin of this embodiment has a crystallization rate (minimum value of semi-crystallization time) of 600 seconds or less, it is possible to carry out stretching orientation crystallization at a temperature higher than Tg while maintaining transparency. Do. When a molded article formed using a polyester resin is stretched, the molecules are oriented and characteristic crystallization called orientation crystallization occurs, and a molded article with greatly improved thermal properties and the like can be obtained. In the stretching orientation crystallization performed at a temperature higher than the Tg, for example, a molded article such as an unstretched sheet is simultaneously biaxially stretched at a temperature 10 to 30° C. higher than the glass transition temperature, for example, 3.5 × 3.5 times. Then, it can carry out by carrying out a heat setting process at 210-230 degreeC for 10 to 30 second.

The sheet formed using the polyester resin of the present embodiment may be a single layer or a multilayer, a film may be a single layer or a multilayer, and even if it is an unstretched one, it is stretched in one direction (uniaxial) or in two directions (biaxial stretching). ) may be used, or may be laminated on a steel plate or the like.

Although it does not specifically limit as a method of obtaining the stretched film containing the polyester resin of this embodiment, A film of a polyester resin is formed into a film by well-known methods, such as extrusion molding and calendering, and 1.1 to 7 times in one direction, It is formed by stretching preferably 2 to 6 times, particularly preferably 2.5 to 5 times, and stretching 1.1 to 7 times, preferably 2 to 6 times, particularly preferably 2.5 to 5 times in a direction perpendicular to the direction. can As a stretching means of a stretched film, methods, such as roll stretching, long gap stretching, tenter stretching, can be applied, Moreover, also in the shape at the time of extending|stretching, methods, such as a flat shape and a tube shape, can be applied. Moreover, it can carry out by sequential biaxial stretching, simultaneous biaxial stretching, uniaxial stretching, or a combination thereof. In addition, the heat set in these extending|stretching can be performed by making a 30-240 degreeC heating zone pass for 1 to 30 second.

As described above, the polyester resin of this embodiment is, for example, an injection-molded article, a sheet, a film (insulating film), an extrusion-molded article such as a pipe, a thermoformed article such as a container, a bottle, a foam, an adhesive material, an adhesive, It can be used for paints, etc. More specifically, the injection molding may be insert molding or two-color molding. Inflation molding may be sufficient as a film. The container may be a molded article obtained by thermoforming a sheet or film such as vacuum forming, air pressure forming, vacuum air forming, or press forming. The bottle may be a direct blow bottle, an injection blow bottle, or injection-molded. In particular, since the molded article formed using the polyester resin of the present embodiment is excellent in transparency, heat resistance, and repeated fatigue properties, a bottle containing the polyester resin can be suitably used, for example, as a bottle requiring repeated use. can The foam may be a bead foam or an extruded foam. In particular, it can be suitably used for applications requiring high heat resistance, such as products used in automobiles, packaging materials for import and export, food packaging materials subjected to retort treatment or microwave heating, and containers such as nursing bottles and tableware subjected to heat sterilization treatment. . Moreover, it can be used suitably for packaging materials, such as a container which UV barrier property is requested|required. That is, the polyester-based injection molded article, the polyester-based extrusion molded article, the polyester-based foam, the polyester-based container, the polyester-based bottle, the polyester-based tableware, and the polyester-based feeding bottle of the present embodiment are each of the present embodiment. It can be said that it contains the polyester resin composition of These will not be specifically limited if the polyester resin of this embodiment is included, It can be set as various well-known forms according to each use.

Example

Hereinafter, although an Example is given and this embodiment is demonstrated in more detail, the range of this embodiment is not limited by these Examples.

1. Preparation of polyester resin

[Example 1]

7919 g of dimethyl terephthalate (DMT), 1786 g of ethylene glycol (EG), spy in a 30 L polyester resin manufacturing apparatus equipped with a decompressor, a record player, a cold trap, a stirrer with a torque detector, a heating device, and a nitrogen inlet tube Roglycol (SPG) 1900 g, 1,4-cyclohexanedimethanol (CHDM) 5535 g, titanium tetrabutoxide (TBT) 1.3879 g, potassium acetate (acetic acid K) 0.8005 g, while raising the temperature to 225 ° C. The transesterification reaction was carried out in a conventional manner.

Next, after the amount of methanol produced by the transesterification reaction becomes 90% of the theoretical amount, 2.3777 g of antimony trioxide (Sb ₂ O ₃ ) and 3.7412 triethyl phosphate (TEP) with respect to the reaction solution g was added. Thereafter, while the reaction solution was maintained at 225°C, the pressure was reduced to 13.3 kPa over 1 hour, and then the temperature was raised and reduced to 280°C and 130 Pa over 1 hour to carry out a polycondensation reaction. Then, the stirring speed was gradually lowered from 100 rpm, the reaction was completed when the stirring speed was 15 rpm and the torque of the stirrer became 140 N·m, and about 8 kg of polyester resin was obtained as a pellet.

[Other Examples and Comparative Examples]

With respect to SPG, CHDM, EG, DMT, TBT, K acetate, TEP, and Sb ₂ O ₃ , except that the input amount was changed according to the table below, in the same manner as in Example 1, to obtain a polyester resin pellet. On the other hand, in Example 3, in Example 1, after the amount of methanol produced in the transesterification reaction became 90% of the theoretical amount, the reaction solution was combined with triethyl phosphate (TEP) and germanium dioxide. (Ge0 ₂ ) was added according to the table below.

On the other hand, Comparative Example 5 and Comparative Example 6 used the following commercially available resin.

Comparative Example 5: Product name "UNIPET RT553C" (manufactured by Nippon Unipet Co., Ltd.)

Comparative Example 6: Product name "Eastar BR203" (manufactured by Eastman Chemical Company)

2. Evaluation of the resin

(Copolymerization rate of diol having a cyclic acetal skeleton)

In the polyester resin, (1) in the diol structural unit, a unit derived from a diol having a cyclic acetal skeleton (SPG), a unit derived from an alicyclic diol (CHDM), and (2) a dicarboxylic acid structural unit , the copolymerization rate of the unit (EG) derived from ethylene glycol, and the copolymerization ratio of the unit (PTA) and isophthalic acid (PIA) derived from terephthalic acid in the dicarboxylic acid unit were calculated by ¹ H-NMR measurement. As the measuring device, "Ascend ^TM 500" manufactured by Bruker BioSpin KK was used. Deuterated chloroform was used as a solvent. On the other hand, when insoluble in deuterated chloroform, a few drops of trifluoroacetic acid were used to dissolve in deuterated chloroform.

(semi-crystallization time)

The semi-crystallization time based on the depolarization intensity method was measured when the pellets produced in each Example and Comparative Example were pressed into a crushed sheet, melted at 280°C and crystallized at constant temperature at 150-230°C. Specifically, it was sandwiched between a cover glass and melted at 280°C for 6 minutes, then placed in a crystallization bath at a predetermined temperature to measure the change in depolarization intensity with time, and the semi-crystallization time at that temperature was determined. The semi-crystallization time was determined by changing the temperature of the crystallization bath from 150 to 230° C. at 10° C. intervals and measuring the semi-crystallization time at constant temperature crystallization, and the smallest value among them was the semi-crystallization time (seconds) of the resin. . A result is shown in Table 2. In addition, in the table|surface, the case where the minimum value of semi-crystallization time was less than 600 second was evaluated as "A", and the case where it was 600 second or more was evaluated as "C".

(Glass transition temperature and crystallization peak calorific value upon temperature drop)

The glass transition temperature (Tg) of the polyester resin was measured by using a differential scanning calorimeter (model: DSC/TA-50WS) manufactured by Shimadzu Corporation, and about 10 mg of the sample was placed in an aluminum unsealed container, nitrogen gas (30 ml/min) It was measured at the temperature increase rate of 20 degreeC/min in an airflow, and the temperature which changed only 1/2 of the difference of the baseline in the transition before and behind the DSC curve was made into the glass transition temperature. A result is shown in Table 2. In addition, in the table|surface, the case where Tg was 100 degreeC or more was evaluated as "A", and the case where it was less than 100 degreeC was evaluated as "C".

The crystallization exothermic peak at the time of temperature decrease was measured from the area of the exothermic peak appearing when the glass transition temperature was measured, maintained at 280° C. for 1 minute, and thereafter, the temperature was decreased at a temperature decrease rate of 10° C./minute.

3. Production of biaxially oriented film

Using the polyester resin pellets obtained in each Example and Comparative Example, extrusion molding was performed under the conditions of a cylinder temperature of 250 to 290°C, a die temperature of 250 to 290°C, and a roll temperature of 75 to 100°C, and a thickness of about 0.5 mm of unstretched sheet was produced.

Next, the unstretched sheet is simultaneously biaxially stretched at 3.5 x 3.5 times at a temperature 10 to 30°C higher than the glass transition temperature, and then heat-set at 210 to 230°C for 10 to 30 seconds, and biaxially stretched to a thickness of 40 µm. got a film.

4. Evaluation of Biaxially Stretched Film

(Heat resistance (heat shrinkage rate))

The biaxially oriented film obtained in 3. above was cut to a size of 10 mm in width and 150 mm in length, along the direction in which the long side (150 mm) coincides with the longitudinal direction, and marks were attached at intervals of 100 mm. The spacing (spacing A) of the marks was measured under a constant tension (length direction) of 5.8 g. Then, it was left to stand for 30 minutes in the oven of 200 degreeC atmosphere with no load. After taking out the film from oven and cooling to room temperature, the space|interval (interval B) of the mark was calculated|required under the constant tension of 5.8 g (longitudinal direction), and the thermal contraction rate (MD) was computed from the following formula. A result is shown in Table 2. In addition, in a table|surface, the case where thermal contraction rate was less than 6 % was evaluated as "A", and the case where it was 6 % or more was evaluated as "C".

Thermal shrinkage (%)=[(A-B)/A]×100

(Heize)

Haze (%) of the biaxially oriented film (thickness: 40 μm) obtained in the above 3. was measured. A result is shown in Table 2.

As is clear from the above table, the polyester resins of Examples had a high Tg, a crystallization rate of less than 600 seconds, and excellent transparency even when crystallized by stretching orientation at a temperature higher than Tg.

In contrast, the polyester resins of Comparative Examples 1, 2, and 4 containing SPG, CHDM and EG, in which the copolymerization ratio of SPG exceeds 20 mol%, and the copolymerization ratio of CHDM is less than 70 mol% among the diol constituent units are all secret It was honesty. For this reason, when extending|stretching orientation crystallization at the temperature higher than Tg, the heat setting after simultaneous biaxial stretching could not be performed, and the film could not be obtained.

In addition, the polyester resin of Comparative Example 3 containing SPG and EG but not containing CHDM, Comparative Example 5 (PET) consisting of EG and PTA, and Comparative Example 6 which was PCT modified with isophthalic acid were crystalline resins, but Tg was low, and the heat resistance was inferior.

The polyester resin of the present invention is excellent in heat resistance and transparency, and stretched films, bottles used repeatedly, products used in automobiles, packaging materials for import and export, food packaging materials subjected to retort treatment or microwave heating, heat sterilization treatment The industrial significance of the present invention is great because it can be suitably used in containers such as nursing bottles and tableware, and applications requiring high heat resistance.

As for the indication of the Japanese Patent Application No. 2019-131846 for which it applied on July 17, 2019, the whole is taken in into this specification by reference.

In addition, all documents, patent applications, and technical standards described in this specification are incorporated by reference in this specification to the same extent as if each individual document, patent application, and technical standard was specifically and individually recorded to be incorporated by reference. is used

Claims (8)

A polyester resin comprising a dicarboxylic acid structural unit and a diol structural unit,
More than 0 mol% and 20 mol% or less of the diol structural unit is a unit derived from a diol having a cyclic acetal skeleton,
70 to 98 mol% of the diol structural unit is a unit derived from a diol having an alicyclic skeleton,
A unit derived from ethylene glycol is included in the diol structural unit,
80 mol% or more of the dicarboxylic acid structural unit is a unit derived from terephthalic acid,
A polyester resin having physical properties represented by the following (A).
(A) The minimum value of the semi-crystallization time based on the depolarization intensity method when melting at 280°C and crystallizing at constant temperature at 150-230°C is 600 seconds or less. The method of claim 1,
The polyester resin, wherein the diol having a cyclic acetal skeleton is at least one selected from compounds represented by the following formulas (1) and (2).
[Formula 1]

(In formula (1), R ¹ and R ² each independently represent an aliphatic group having 1 to 10 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms.)
[Formula 2]

(in formula (2), R< ¹ > is the same as that of formula (1), and R< ³ > represents a C1-C10 aliphatic group, a C3-C10 alicyclic group, or a C6-C10 aromatic group. ) 3. The method of claim 1 or 2,
Poly, wherein the diol having a cyclic acetal skeleton is 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, ester resin. 4. The method according to any one of claims 1 to 3,
The polyester resin wherein the diol having an alicyclic skeleton is 1,4-cyclohexanedimethanol. 5. The method according to any one of claims 1 to 4,
The polyester resin whose content of the unit derived from the said ethylene glycol among the said diol structural units is 0.1-10 mol%. The molded object containing the polyester resin in any one of Claims 1-5. The stretched film containing the polyester resin in any one of Claims 1-5. The bottle containing the polyester resin in any one of Claims 1-5.